This invention relates to a method of manufacturing a circuit module that uses synthetic resin.
In the prior art method of manufacturing a circuit module, a copper foil formed on the resin substrate is selectively etched to form the circuit pattern of the printed circuit board to which electronic elements such as ICs and capacitors are soldered or connected by conductive bonding. With this method it is possible to use a wiring board in which a circuit pattern is formed on a substrate made of a ceramic such as alumina by means of thick film printing, instead of a printed circuit board.
The thickness of a circuit module obtained in this way is the total of the thickness of the substrate and the thickness of electronic elements, and, accordingly, the thickness that results when this method of manufacture is used is too great for electronic devices requiring ever decreasing size. Also, with this method of manufacture the process of manufacturing the printed circuit board and the process of mounting the electronic elements on the board are performed independently, complicating the manufacturing process, and increasing the time and cost.